Kirsten murine sarcoma virusSarcoma Viruses, MurineGammaretrovirusMoloney murine sarcoma virusCell Transformation, ViralCell Transformation, NeoplasticHarvey murine sarcoma virusOncogenesAvian Sarcoma VirusesGenes, ViralGenes, rasSarcoma, ExperimentalMoloney murine leukemia virusCell LineHelper VirusesSarcomaLeukemia Virus, MurineDNA Restriction Enzymes